Rails

Question 1

What types of associations can models have in RoR?

Answer 1

belongs_to
has_one
has_many
has_and_belongs_to_many
polimorphic
self joins

Question 2

What’s a gem?

Answer 2

Packaged Ruby code, ready to be reused across projects.

Question 3

What does MVC stand for?

Answer 3

Model View Controller

Question 4

What’s the naming convention for models in Rails?

Answer 4

Singular, camel-cased nouns.

E.g. BookClub

Question 5

What’s the naming convention for tables in Rails?

Answer 5

Pluralized, snake-cased nouns.

E.g. book_clubs

Question 6

What’s the naming convention for controllers in Rails?

Answer 6

Pluralized, camel-cased nouns, suffixed with the term “Controller”.

E.g. BookClubsController

Question 7

What’s a callback in the context of RoR?

Answer 7

It’s a method that gets called at certain moments of an object’s life cycle (e.g. when an Active Record object is created, saved, updated, deleted, validated, or loaded from the database).

Question 8

What does ORM stand for?

Answer 8

Object Relational Mapping

Question 9

What is Object Relational Mapping?

Answer 9

It is a technique that connects objects to tables in a relational database.

Using ORM, the properties and relationships of the objects in an application can be easily stored and retrieved from a database without writing SQL statements directly.

Question 10

What’s Active Record?

Answer 10

Active Record is Ruby on Rails’ ORM framework.

Question 11

What does “convention over configuration” mean?

Answer 11

Rails has a set of conventions (naming conventions and schema conventions); if you follow them, you’ll spare yourself from writing configuration code.

E.g. If your model is named “BookClub”, Rails will expect it to be related to a table named “book_clubs”; respecting that convention will keep your code free from configuration code.

Question 12

What is “eager loading?

Answer 12

It’s a mechanism for loading associated records more efficiently.

Question 13

Which methods does RoR provide for eager loading?

Answer 13

includes
preload
eager_load

Question 14

What’s wrong with this code?

Project.where("name = '#{params[:name]}'")

Answer 14

It’s vulnerable to SQL injection.

Question 15

How can you access sensitive credentials in RoR?

Answer 15

Rails.application.credentials